Fatigue and pain are two of the most common and troublesome problems experienced by oncology outpatients. Clinical experience and our pilot data suggest that sleep disturbances occur in this patient population and can influence daytime fatigue and daytime activity. This descriptive correlational study will be the first to describe the patterns of change in fatigue, pain, and sleep disturbances over the course of radiation therapy (RT) in oncology outpatients with four specific diagnoses (i.e., breast cancer, prostate cancer, brain tumors, and lung cancer). In addition, these same symptoms will be evaluated in the patient's family caregiver. Participants will be recruited at the time of the patient's simulation visit in the RT department. Patient/caregiver dyads will be followed over the course of RT and for four months following the completion of RT (i.e., a total of 17 assessments). In addition to describing the patterns of change in these three symptoms, the relationships between fatigue severity and salient physiological (i.e., hemoglobin, hematocrit, interleukin-6 levels) and psychological variables (i.e., anxiety, depression, quality of life, caregiver strain (only in the family caregivers)) will be determined. Patients and family caregivers will be asked to list the self-care behaviors they use to manage pain, fatigue, and sleep disturbances over the course of RT and following treatment. These data will provide important information to begin to plan intervention studies for patients who are undergoing RT. Inclusion of family caregivers in this research is extremely important given the shift in oncology services from the inpatient to the outpatient setting.